Multiple-filament electric-lamp headlight



- May 15, 1923. 1,455,033

. H. H. SLATER MULT IPLE FILAMENT ELECTRIC LAMP HEADLIGHT Filed July 15 1921 Patented Ma -115.1923.

mmvmr' a. sauna, or xnuosn'a; WISCONSIN.

. MULTIPLE-FILAMENT ELECTRIC-LAMP HEADLIGHT.

Application filed July 15, 1921. Serial No. 484,858;

To all whom it may concern:

Be it known that I, HARVEY H. SLATER, a citizen of the United States, residing at Kenosha,in the county of Kenosha and State of Wisconsin, have'invented certain new and useful Im rovements in Multiple- Filament Electricamp Headlights, of which-the following is a specification.

My invention relates to headlights, searchlights, and similar appliances employing incandescent filament electric lamp bulbs and associated reflectors, but pertains more particularly, yet not exclusively, to lights of this general kind employed on automobiles.

' With such equipments, it is desirable or essential to provide a powerful,. iercing,

bright light which will be projected a considerable distance without serious or ma-.

terial dispersion, and also to employ means for supplying a much dimmer light which will not daze or temporarily blind or inconvenience a person facing it. Y

The former intense light is ordinarily used for country driving, but since such brilliant and dazzling light, while' well adapted for its purpose, is unsuited for city or town driving, the dimmer and less bright light is employed.

My improved and novel headlight structure is of the single bulb multiple filament type with two filaments, desirably though not necessarily of equal brilliancy, each located close to butnot at the focus of the 3 ,,reflector, whereby either filament may be rendered, incandescent for dim lighting,

whereas, both filaments may be simultaneously supplied with electric current for I bright lighting. Preferably the twofila- 40 ments are arranged symmetrically on opposite sides of the axis ofthe reflector near but neither at the. focal center thereof. Owing to such slightly out-of-focus arrangement, when either filament is heated ts light rays although more or less brilliantare sufiiciently dlspersed or dissipated so that a person facin the headlight is not at all inconvenience When the two filaments are rendered simultaneously incandescent, they in effect, due to their proximity to one another and tothe focus of the reflector, in large measure form the equivalent of an incandescent filament at such focal center, .producing a piercing brilliant light such as is required for some kinds of axis of'the reflector.

automobile driving as explained above. The light raysabsent when either filament alone is incandescent are supplied by the com-- panion filament when bothyare heated at thesame time.

Stated somewhat "otherwise, the light beams of each filament form a complement of those of the companion filament and compensate for its-lack offocal'brill ancy', j v

thelight rays from the two filaments unitedly and conjointly functioning to 'pro- ,duce the required efi'ulgence and brightness equivalent to the use of a single filament of i proper and adequate candle focus of the reflector.

If for any reason, as by being'burned out,

power at the either out-of-focus filament becomes useless or destroyed, the other can be used as a suitable substitute for reduced lighting] efi'ect. I

To enable those skilled in this art to have a full and complete understanding of this invention and its various structural and functional advantages, I have illustrated a desirable and preferred. embodiment'of the Invention in the accompanying drawing, the single figure of which shows an automobile headlight incorporating the invention in vertical section with the wiring illustrated more or. less diagrammatically.

Referring to the drawing, it will be perceived that the improved headlight structure comprises a main, hollow, sheet-metal body 10 of the usual general parabolic or w other appropriate shape equipped at its front with a round, protective glass 11 demountabl or detachablyheld in place by any suita le or usual means. nternally such sheet-metal body accommodates the customary polished refector 12 equipped at its center with a rearwardly-- extended lamp socket 13 of appropriate or any usual design ermitting adjustment of the-electric lamp bulb forwardly or backwardly for proper and correct positioning thereof? Such socket is designed and adapted to re- 7 ceive and make suita the stem or base 15 of an electric lamp bulb 14 equipp d internally with a' air of concentrated laments 16 and 17 0 equal light intensity when heated and arranged close to and at equal distances on opposite sides of the focal center point of the principal le electric contact with i Neither filament, is at, but both are close to and on opposite sides of, the focus of the reflector. A

Accordingly when either filament is made incandescent, it gives a brilliant white light,

but, owing to the fact that it is'out of focus, the emitted light rays are sufficiently scattered and dispelled so as not to be dazzlingor blinding to a person in front of the headlight.

On the other hand, when both filaments are heated at the same time, they su plement and complement one another, pro ucing in ,some degree, owing to their nearness to one another and because of their contlgui-ty and proximity to the focus of the reflector, in eflect a single resultant filament at the focal center. with r the consequent concentrated brilliant light required at times and which would not be suitablevfor city or town driving.

such filaments singly or combinedthe appliance is provided with the three wires 18, 19 and 20, the wire 18 being connected to both filaments, the wires 19 and 20 being connected to the other ends of the filaments and to two terminals 21 and 22 of an electric switch '23 connected by a' wire-24 to the source of electric current associated withwire 18. Switch 23, consisting of a conducting straight arm with an arcuate end portion, may be shifted to cause such curved part to contact with either terminal 21 or 22 and cause the incandescence' of either one For the control of theelectric heating ofof the pair of filaments or it may connect,

with both terminals at the same time, the p v curved part being of suflicent length to engage both switch terminals 21 and 22 concurrently, causing the simultaneous], heating of the two filaments.

While I have herein described and in the drawing have illustrated a single preferred embodiment of the invention, those skilled in this art will understand that the invention is susceptible of a' variety of embodiments and is not limited and restricted to the precise and exact mechanical details presented since these may be modified within comparatively wide limits without departure from the substance and essence o the invention'and without the sacrifice of any of its substantial benefits and advantages.

1 claim:

In :a head-light construction of the char- HARVEY H. SLATER. I

55, acter described, the combination of a re- 

